John Schmid (August AD2000) raised a profound point on Evolution/Original Sin: "Church teachings are concerned with doctrine - what we are obliged to believe."
Teachings defined in Tradition - and thus obligatory upon Catholics to believe - include:
* Official declaration against human evolution.
Leo XIII in the encyclical Arcanum Divinae Sapientiae (1880) taught that the first parents Adam and Eve were specially created and the body of Eve was created from a portion of Adam's body. This leaves no room whatsoever for evolution of human beings.
* Official declaration against polygenism (i.e., many "first parents").
In the 1994 Catechism approved by John Paul II, polygenism was effectively rejected (see para 360, footnote 226 reference to the RSV Book of Tobit 8:6: "Thou madest Adam and gavest him Eve his wife as a helper and support. From them the race of mankind has sprung." The "one ancestor" referred to in the CCC can only be Adam and not "many first parents". In Humani Generis (1950), polygenism was heavily frowned upon by Pius XII. Fr J. Franklin Ewing SJ, Professor of Anthropology and a theistic evolutionist, wrote in Human Evolution (1956) that he was personally convinced that Pius XII had taught that polygenism is in fact irreconcilable with the doctrine of Original Sin.
Leo XIII also taught in Providentissimus Deus (1893) that we must take great care to be guided by the Church Fathers, who are most important in Tradition. He warned that we must not play one off against another but instead believe what they were unanimous in, or near-unanimous in. Almost all of them held to ex nihilo special creation of kinds each "in its whole substance" and the majority who wrote on it held to creation days of 24 hours each. (See Robert Sungenis, The History of the Catholic Doctrine of Creation.) It is self-evident that interdependence and symbiosis within life forms requires rapid, almost concurrent creation.
It is essential to clarify terms. Evolution is all about the natural gaining of "higher", genetic information not possessed by one's ancestors. Natural selection does not do this. Professor Maciej Giertych, in his foreword to Creation Rediscovered, shows that evolution did not occur because it cannot occur. Our great Creator/Redeemer chose to design life forms so that plenty of changes occur - within kind, but never beyond kind.
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